Interpretive Summary: The mechanisms that regulate glucose in chickens are not fully understood. The effect of fasting on glucose concentrations and the glucose regulatory hormones in the modern meat-type chicken has not been studied. Early reports in the literature are inconsistent with regards to changing glucose concentrations as affected by feeding and fasting. Similar findings have been reported for hormones from the pancreas, glucagon and insulin, that regulate the level of glucose in the blood stream. This study compared the effects of fasting on circulating levels of glucose, insulin and glucagon in modern male and female meat-type broiler chickens. Based on the findings in this study, it is critical to understand the physiological control of glucagon secretion in chicken more fully. Results of this investigation will be of interest to avian and poultry scientists.

Technical Abstract:
The present study compared the effects of fasting on circulating concentrations of glucose, insulin and glucagon in male and female modern meat-type chickens (Ross 708) at three ages (19 d, 33 d and 47 d). Plasma concentrations of glucose were reduced by fasting with reductions of 24.9% (19-d-old), 22.6% (33-d-old) and 17.9% (47-d-old) in broiler chickens fasted for 12 h. Plasma concentrations of insulin decreased with fasting. For instance, circulating concentrations of insulin declined after 6 h of fasting by 45.7%, 54.7% and 50.0%, respectively, in 19-d-old, 33-d-old and 47-d-old broiler chickens. Plasma concentrations of glucagon were increased by fasting. Plasma concentrations of glucagon were elevated by 3.79% (19-d-old), 3.51% (33-d-old) and 3.79% (47-d-old) with 6 h of fasting and remained elevated with 12 h, 18 h and 24 h of fasting.